Locating a terminal has important significance in emergent events or events involving the national security. An existing general method is shown in FIG. 1, in which a Gateway Mobile Location Center (GMLC for short) sends a location selecting routing message to a Home Location Register (HLR for short) to obtain an address of a mobile switching center to which a terminal belongs, then sends a location request message to a mobile switching center (MSC for short) to obtain location parameters of the terminal, and calculates location information of the terminal. However, since some network elements in communication systems are applicable to earlier protocol versions or implement single function, and don't support location selecting routing signaling, the expense of modifying such communication network elements are huge; in addition, sometimes the location information of the terminal cannot be obtained for reasons on network.